INTRODUCTIONDefensive medicine is defined as medical practices that may exonerate physicians from liability without significant benefit to patients. Many studies have argued that defensive medicine is a major cost driver in healthcare; however, the national prevalence of defensive medicine in the field of orthopaedic surgery has not been investigated. The purpose of this study is to investigate the practice of defensive medicine and the resultant financial implications of such behavior by orthopaedic surgeons in the United States.METHODSIn September of 2010, 2000 orthopaedic surgeons randomly chosen from the AAOS registry received invitations to answer a web-based survey on defensive medicine. Of these, 1,214 (61%) completed the survey. Cost analysis was performed using Center for Medicare and Medicaid (CMS) data, which were provided at the 2011 CPT code level and then aggregated to reflect the eight domains of care assessed in this study.RESULTSOf the 1,214 respondents, 1,165 (96%) reported having practiced defensive medicine by ordering imaging, laboratory tests, specialist referrals or hospital admissions mainly to avoid possible malpractice liability. On average, 24% of all ordered tests were for defensive reasons (radiography, 19%; CT scanning, 26%; MR imaging, 31%; ultrasound, 44%; referrals, 35%; laboratory tests, 23%; and biopsies, 18%). Defensive hospital admissions averaged 7% each month. Using the average national Medicare payment information from the 2011 CPT code reimbursement data, the cost of defensive medicine per respondent was calculated to be approximately $8,500 monthly or approximately $100,000 per year, which is roughly 24% of each physician’s spending. Given the U.S. Department of Labor’s statistic of 20,400 practicing orthopaedic surgeons in the United States, this study estimated that the national cost of defensive medicine for the specialty of orthopaedic surgery is $173 million per month and $2 billion annually.DISCUSSION AND CONCLUSIONDefensive medicine among orthopaedic surgeons is a significant factor in healthcare costs and of marginal benefit to patients. Policies aimed at managing liability risk may be useful in containing such practices.